Method and apparatus to improve wake flow and power production of wind and water turbines

ABSTRACT

A wake flow injector method and apparatus are presented to improve the power production of wind and water turbines by directly injecting higher-energy fluid or air directly into the wake flow region behind the rotor or turbine.

CROSS-REFERENCE TO RELATED APPLICATIONS

U.S. Utility patent application Ser. No. 12/803,079 Filed Jun. 18, 2010,Applicant: Keith Michael Werle, Atlanta, Ga., U.S. Provisional PatentApplication No. 61/269,606 Filed Jun. 26, 2009, “Method and Apparatus toImprove Wake Flow and Power Production of Wind and Water Turbines”.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE LUSTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

The present invention is in the general field of turbines. Moreparticularly, the present invention is in the technical field of windturbines and water turbines.

One of the fundamental principals governing all wind turbines, open-flowhydro (water) turbines and ocean tidal or current turbines is that thetotal power that can be harvested from a given flow of air or fluid isconstrained by, among other things, the velocity and pressure of thefluid or air in the wake of the rotor. In layman's terms, as the wateror air passes through a turbine, the turbine harvests energy from theflow across the turbine blades. After passing through the turbine, theair or water has less energy than it did before passing through theturbine. Since the volume of the flow is unchanged by the turbine, thelower energy flow behind the turbine has a reduced average pressure. Asthis low energy/low pressure flow moves downstream, it's pressure mustrise back to the overall ambient level, which causes the flow velocityto decrease as it proceeds aft of the turbine. This slower moving air orfluid in the wake behind the turbine impacts the upstream flow by“damning up” the flow—thus limiting the flow speed and the volume at theturbine rotor.

This principal is at the heart of what is known as the “Betz” limit.First documented by A. Betz in 1926, the calculated theoretical limit ofan “open flow” rotor to convert fluid (or wind) power to rotating poweris 59.3% of the total energy or power of the ambient, or unobstructedflow contained within the swept area of the turbine rotor. Thistheoretical limit, or maximum efficiency is derived from the ratio ofthe ambient up-stream velocity (V1) and the terminal, or wake velocityof the fluid or air right after it passes through the turbine rotor(V2).

Ducted or shrouded turbines are not subject to the “Betz” limit andoften achieve efficiencies well above the 59.3% maximum for open-flowturbines. A recent theoretical breakthrough for calculating the maximumefficiency for ducted or shrouded turbines (with and without injectionof bypass fluid), like their open-flow counterparts, shows that they arestill subject to the same impacts from their wake-flow velocities.

However, the duct or shroud around a turbine offers designersopportunities to employ a number of aerodynamic effects to improve thewake flow. These effects can be in the form of vanes or crenulated edgesdesigned to induce down-stream axial vortices in the wake flow. Theseentrained vortices can rapidly mix higher energy bypass flow fromoutside the shroud with lower energy, slower moving flow in the wake.The impact of this is to more rapidly “mix-out” the wake, and increasethe efficiency of the turbine. This is also referred to as energizing,or re-energizing the wake-flow.

The impact of this is to increase the velocities of the flow in the wakearea and more rapidly clear the low-energy, slower moving flows from theback of the turbine. This allows more air or fluid to pass through theturbine, at higher velocity, and thus more energy can be captured.

However, these methods, which represent the prior art in the field, arelimited by the flow area at the circumference, or outer diameter of theshroud. Prior art is not only limited by the total area at the boundary,but it is also limited by a number of other constraints—including theability to capture energy from a particular target area in or around theprimary or bypass flow and re-direct that energy to specific area withinthe wake-flow.

BRIEF SUMMARY OF THE INVENTION

The present invention is method and apparatus to directly injecthigh-energy fluid or air directly into the wake flow region of a wind orwater turbine, thereby re-energizing the wake flow and more rapidly“mixing out” the slower moving air or fluid behind a turbine rotor.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1. is a side view of the present invention deployed on a ductedopen flow hydro-turbine.

FIG. 2. is a frontal view of the embodiment of present invention shownin FIG. 1.

FIG. 3. is a side view of the present invention with two wake flowinjectors installed on a ducted open flow hydro-turbine of similarembodiment to FIG. 1.

FIG. 4. is a frontal view of the present invention with two wake flowinjectors installed on a ducted open flow hydro-turbine of similarembodiment to FIG. 1.

FIG. 4A. is a frontal view of the present invention with four wake flowinjectors installed on a ducted open flow hydro-turbine of similarembodiment to FIG. 1.

FIG. 5. is a top view of an alternate embodiment of the presentinvention. In this embodiment, there are four wake flow injectorsdeployed on an open flow tidal turbine designed to extract energy fromthe flow of water into and out of an ocean tidal area. Duringalternating incoming and outgoing tidal flows, the flow of water is fromright to left or left to right on the figure presented. There are twowake flow injectors deployed in each of the relevant flow directions. Asimple flap or closing mechanism 90 is added to the outlet of wake flowinjector to prevent the reversing flow into the outlets of each wakeflow injector during reverse flow periods.

FIG. 6. is a side view of the embodiment of the present invention shownin FIG. 5.

FIG. 7. is a frontal view of the embodiment of the present inventionshown in FIG. 5.

FIG. 8. is a top view of an alternate embodiment of the presentinvention. In this embodiment, two wake flow injectors 10 have separateinlets 20 but share a single outlet 30A within the wake flow region.

FIG. 8A. is a frontal view of the embodiment of the present inventionshown in FIG. 8.

FIG. 9. is a top view of an alternate embodiment of the presentinvention. In this embodiment, there are three wake flow injectors. Twowake flow injectors outside the upstream diameter of the shroud or ductintake as shown above, as well as a third wake flow injector in thecenter of the shroud or duct. This center wake flow injector has aninlet 20, a pipe or tube 10 passing through the center axel area, and anoutlet 30 behind the rotor or turbine blades.

FIG. 10. is a top view of an alternate embodiment of the presentinvention similar to that shown in FIG. 9. In this embodiment, thecenter wake flow injector has a different diameter and length than thetwo radial, or perimeter wake flow injectors.

FIG. 11. is a top view of an alternate embodiment of the presentinvention similar to that shown in FIG. 9. In this embodiment, thecenter wake flow injector has a larger diameter and shorter length thanthe two radial, or perimeter wake flow injectors. In this embodiment,the turbine rotor or blades are centered around either a large diameteraxel or is of a “centerless” or hubless” design configuration. Theintake 20 of the central wake flow injector is just in front of theturbine rotors and the outlet 30 is just behind the turbine rotor andjust inside the wake flow area.

FIG. 12. is a top view of an alternate embodiment of the presentinvention similar to that shown in FIG. 11. In this embodiment, thethree wake flow injectors are deployed on a turbine with a straight ductor shroud.

FIG. 12A. is a frontal view of the alternate embodiment presented inFIG. 12.

FIG. 13. is a top view of an alternate embodiment of the presentinvention. In this embodiment, only a single centered wake flow injectoris deployed on a turbine with a short, asymmetric shroud or duct.

FIG. 14. is a top view of an alternate embodiment of the presentinvention. In this embodiment, only a single centered wake flow injectoris deployed on a turbine with a short, symmetric shroud or duct.

FIG. 14A. is a frontal view of an alternate embodiment of the presentinvention shown in FIG. 14.

FIG. 15. is a top view of an alternate embodiment of the presentinvention. In this embodiment, only a single centered wake flow injectoris deployed on a turbine with a short, symmetric shroud or duct thatalso acts as a structural outer-ring or support of the turbine rotorblades 150.

FIG. 15A. is a frontal view of the alternate embodiment of the presentinvention shown in FIG. 15.

FIG. 15B. is a frontal view of the alternate embodiment of the presentinvention shown in FIG. 15 utilizing turbine rotor and stator typeblades.

FIG. 16. is a side or top view of an alternate embodiment of the presentinvention. In this embodiment, the wake flow injector has an inlet 120or source that is outside the primary and secondary (bypass) flow.

FIG. 17. is a side view of an alternate embodiment of the presentinvention. In this embodiment, a turbine is shown with no shroud or ductand a single wake flow injector centered in the turbine or rotor blades.The wake flow injector has an inlet 20 just in front of the turbineblades, a pipe or tube 10 and an outlet 30 just behind the rotor in thewake flow area.

FIG. 17A. is a frontal view of the alternate embodiment of the presentinvention shown in FIG. 17.

FIG. 18. is a side view of an alternate embodiment of the presentinvention. In this embodiment, a turbine is shown with no shroud or ductand a single wake flow injector centered in the turbine or rotor blades.The wake flow injector has an inlet 20 just behind the turbine blades, apipe or tube 10 and an outlet 30 just behind the rotor in the wake flowarea.

FIG. 18A. is a frontal view of the alternate embodiment of the presentinvention shown in FIG. 19.

FIG. 19. is a perspective view of an alternate embodiment of the presentinvention. In this embodiment, a centered wake flow injector is deployedon a turbine with no shroud or duct as in FIG. 18. This embodiment alsoincludes two wake flow injectors with inlets 20 in the bypass flow aboveand outside the diameter of turbine swept and outlets 30 inside the wakeflow area behind the turbine blades.

FIG. 20. is a frontal view of an alternate embodiment of the presentinvention. In this embodiment, a centered wake flow injector is deployedon a turbine with a shroud or duct having a squared opening on inlet.

FIG. 21. is a frontal view of an alternate embodiment of the presentinvention. In this embodiment, a number of turbines of the type shown inFIG. 20 are deployed in a matrix layout all having the same frontalorientation into the direction of fluid or air flow and parallel axes ofrotation. In this embodiment of the present invention, the matrix ofturbines is deployed with a number of wake flow injectors of similarembodiment presented earlier in FIG. 1 through 19. In this embodiment,each turbine is shown with a center wake flow injector through the axisof rotation. In addition, the matrix is shown with a number of bypasswake flow injectors deployed around the periphery as well as in betweenthe individual turbines.

FIG. 21A. is a frontal view of an alternate embodiment of the presentinvention. In this embodiment, a number of turbines of the type shown nFIG. 20 are deployed in a matrix layout as shown in FIG. 21. In thisembodiment of the present invention, the matrix is shown with a thebypass wake flow injectors deployed in between the individual turbinesare shown as having square or non-circular inlets 10A and/ornon-circular outlets 30A.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the invention in more detail in FIG. 1 and FIG. 2,there is shown a turbine with a duct or shroud 40, a rotor or turbineblades 60 attached to a center axel of rotation 80, supported by staysor struts 70 that hold the axel and turbine in place. In addition, thepresent invention in FIG. 1 and FIG. 2 is shown with a duct, pipe ortube 10 having an inlet 20 and an outlet 30 with a crenulated trailingedge; this sub-assembly in this presented embodiment of the presentinvention is referred to as the wake flow injector.

Referring now to the invention in more detail in FIG. 1 and FIG. 2, inFIG. 1, the fluid or air flow is from left to right. The fluidapproaching directly in front of the shroud 40 opening is directed intothe shroud and accelerated across the turbine rotor blades 60. Theturbine rotor blades 60 extract energy from the flow through the shroud40. The lower energy, slower moving fluid exits behind the rotor 60 andflows into the wake area downstream. The upstream fluid or air flow thatis outside the area directly in front of the shroud 40 flows outside theshroud 40 on all sides. This flow outside the shroud 40 or turbine 60 isconsidered the bypass flow. The bypass flow directly in front of theinlet 20 for the bypass intake pipe 10 above and outside the shroud 40enters the bypass tube or pipe 10. The fluid or air flow that enters thebypass tube or pipe 10 is directed down the pipe 10 and exits into thewake flow area via the outlet 30.

The present invention of the embodiment presented in FIG. 1 and FIG. 2should be deployed with sufficient distance from obstacles,obstructions, embankments or other turbines so as to allow forundisturbed bypass flow around the sides, top and/or bottom of theshroud—or turbine blades if no shroud or duct is employed.

In the present invention of the embodiment presented in FIG. 1 and FIG.2, the source of the bypass wake flow injector inlet 20 need not be frombypass flow outside or directly adjacent to the primary flow. Thealternate embodiments of the present invention demonstrating this arepresented below in FIG. 9 through FIG. 19 below.

In the present invention of the embodiment presented in FIG. 1 and FIG.2, the inlet 20 need not be round and the pipe or tube 10 and outlet 30need not be of the same shape or diameter as other the other componentsof the wake flow ejector 10. Nor does the pipe or tube 10 need to be ofthe same shape or diameter from one end to the other. The shapes anddiameters of the components are best determined by the particularapplication and/or embodiment of the present invention and theconditions under which it will operate. Similarly, the aerodynamiceffects employed at the trailing edge of the outlet 30 need not be of asimple crenulated form.

Referring now to the invention in more detail in FIG. 1 and FIG. 2, thematerials used for the bypass wake flow ejector pipe 10 should be ofsufficient stiffness to avoid structural failure and excessive vibrationduring expected operating conditions. Similarly, the material shouldalso be of sufficient strength and have sufficient support to avoidwarping or distortion of the pipe 10, the inlet 20 or outlet 30.

The material used for the wake flow ejector pipe 10 should be relativelysmooth along the inside diameter of the inlet 20, the pipe or tube 10and the outlet 30 to minimize drag and turbulence of the bypass fluid orair flowing through the bypass wake flow injector.

Referring now to the invention in more detail in FIG. 5, FIG. 6 and FIG.7, there is shown four wake flow injectors with inlets 10, a pipe ortube for each 20 and an outlet 30 for each. In this embodiment, thebypass wake flow injectors are deployed on an open flow tidal turbinedesigned to extract energy from the flow of water into and out of anocean tidal area. During alternating incoming and outgoing tidal flows,the flow of water is from right to left or left to right on the figurepresented. There are two wake flow injectors deployed in each of therelevant flow directions. A simple flap or closing mechanism 90 is addedto the outlet of each wake flow injector to prevent the reversing flowinto the outlets of each wake flow injector during reverse flow periods.

Referring now to the invention in more detail in FIG. 8 and FIG. 8A,there is shown an embodiment of the present invention similar to that ofthe primary embodiment shown in FIG. 1 and FIG. 2. In this embodiment,the outlet 30 is shared by both wake flow injectors with inlets 20. Bothwake flow injectors share a common outlet 30 with a large diameter,crenulated trailing edge located at or near the center of the wake flowarea behind the rotor or turbine blades.

Referring now to the invention in more detail in FIG. 9 through FIG.15B, there is shown a number of embodiments of the present inventionthat include a wake flow injector located along the center axis of therotor or turbine blades. This center wake flow injector has an inlet 20located in the area directly in front of the rotor turbine blades and apipe or tube 10 that passes through the center axis or hub of theturbine and an outlet 30 behind the turbine in the wake flow area. Inthis embodiment, high energy flow is directed from an area directly infront of the swept area of the turbine rotor or blades and is passedthrough the center of the turbine and injected into the wake flowdirectly behind the rotor.

Referring now to the invention in more detail in FIG. 16, there is shownan embodiment of the present invention similar to that of the primaryembodiment shown in FIG. 1 and FIG. 2. In this embodiment the wake flowinjector has an inlet 120 or source that is outside the primary andsecondary (bypass) flow. The source of the bypass wake flow injectorinlet 20 can be from a separate or outside source from the primary orbypass flows. This secondary, or outside source could include a nearbyintersecting stream, rainwater nm-off, industrial or commercial waterrelease, or in the case of a wind turbine, a nearby steam, blown coolingtower release or pressurized exhaust source.

Referring now to the invention in more detail in FIG. 17 and FIG. 17A,there is shown an alternate embodiment of the present invention deployedon open flow hydro and wind turbines without ducts or shrouds. In FIG.17 and FIG. 17A, the open flow hydro turbine has a large diameter centeraxel, hub or ring with a centered wake flow injector.

Referring now to the invention in more detail in FIG. 18 and FIG. 18A,there is shown an alternate embodiment of the present invention deployedon traditional three bladed wind turbine without a duct or shroud. Inthis embodiment of the present invention, the turbine is deployed with alarge diameter centered wake flow injector with an inlet 20 that isdirectly behind the rotor turbine blades, a short tube or pipe 10 and anoutlet 30 that is inside the wake flow area down stream.

Referring now to the invention in more detail in FIG. 19, there is showna perspective view of the embodiment of the present invention shown inFIG. 18 and FIG. 18A and includes an additional two bypass wake flowinjectors; one with intake 20 in the upper left area of the bypass flowoutside the primary flow area, and one with intake 20 in the upper rightarea of the bypass flow outside the primary flow area.

Referring now to the invention in more detail in FIG. 21, in thisembodiment of the present invention, a number of turbines of the typeshown in FIG. 20 are deployed in a matrix layout all having the samefrontal orientation into the direction of fluid or air flow and parallelaxes of rotation. In this embodiment of the present invention, thematrix of turbines is deployed with a number of wake flow injectors ofsimilar embodiment presented earlier in FIG. 1 through 19. In thisembodiment, each turbine is shown with a center wake flow injectorthrough the axis of rotation. In addition, the matrix is shown with anumber of bypass wake flow injectors deployed around the periphery aswell as in between the individual turbines.

While the foregoing written description of the invention enables one ofordinary skill to make and use what is considered presently to be thebest mode thereof, those of ordinary skill will understand andappreciate the existence of variations, combinations, and equivalents ofthe specific embodiment, method, and examples herein. The inventionshould therefore not be limited by the above described embodiments,methods, and examples, but by all embodiments and methods within thescope and spirit of the invention as claimed.

1. A device or apparatus comprising; a) a wind or water turbinecomprising one or more horizantal axial flow turbines, propellers,stator, fans, impellors, or any combination thereof, adapted in size andshape so as to harness power from a flow or stream of a fluid (includingair or water) and convert it to mechanical or electrical energy (orpower) and, b) one or a plurality of pipes, tubes, ducts, hoses,plenums, conduits, channels or other such devices or elements, adaptedin size and shape so as to introduce, direct, or eject a flow, stream orstreams of fluid, including air or water, into the primary stream flowarea behind or aft of the propeller, fan or turbine (also called thewake flow area) so as to change the velocity, direction, turbulence,pressures, mixing or other flow properties of the primary fluid or airflow in the wake.